Canister vacuum cleaners having a mains power supply cord are generally known in the prior art. Such vacuum cleaners have the disadvantage that a mains power outlet must be within their reach to supply power thereto. This is not always the case, especially when cleaning stairs or vehicles, so that extension cords must be used, which reduces the ease-of-use. Also known are vacuum cleaners which can be operated independently of the mains supply. In order to enable said vacuum cleaners to operate in self-contained mode, a power supply module is provided which may contain one or more rechargeable battery cells. European Patent Document EP 0 401 531 B1, for example, describes a vacuum cleaner whose housing has a cavity therein which is externally accessible and used to accommodate a removable battery assembly. The vacuum cleaner disclosed therein has means for removably holding the battery assembly within the cavity. In vacuum cleaners which are powered by non-rechargeable or rechargeable batteries, due to the high power consumption of the suction fan, the energy storage capacity is usually not sufficient to allow thorough cleaning of a large carpet, or of a room having a wall-to-wall carpet, so that the battery must be repeatedly recharged. This also reduces the ease-of-use.
Further, DE 10 2004 018 793 A1 describes an electrical floor-cleaning apparatus having a chamber adapted to receive either a power supply module or a cord reel module. This apparatus allows the decision as to whether the vacuum cleaner is to be produced for mains operation or for battery operation to be taken at a late stage in the manufacturing process, but ultimately the product is a vacuum cleaner that has only one of the two alternative modes of operation and the associated disadvantages. Except for the option of employing either a rechargeable battery or a cord reel, no further adjustments are made. It may therefore be assumed that the fan motor is designed to operate at a mains voltage of 230 volts. In the case of power supply from a rechargeable battery, the operating voltage would be reduced to at least one third of said voltage, as a result of which the maximum power would be reduced to one-ninth compared to that in mains operation. Consequently, satisfactory operation in battery mode would no longer be possible.